title: Thirst in critically ill patients: from physiology to sensation.
abstract: Critically ill patients often report distressful episodes of severe thirst, but the complex biochemical, neurohormonal mechanisms that regulate this primal sensation still elude clinicians. The most potent stimuli for thirst are subtle increases in plasma osmolality. These minute changes in osmolality stimulate central osmoreceptors to release vasopressin (also known as antidiuretic hormone). Vasopressin in turn acts on the kidneys to promote the reabsorption of water to correct the increased osmolality. If this compensatory mechanism fails to decrease osmolality, then thirst is triggered to motivate drinking. In contrast, thirst induced by marked volume loss, or hypovolemic thirst, is subject to the tight osmoregulation of the renin-angiotensin aldosterone system and accompanying adrenergic agonists. Understanding the essential role that thirst plays in salt and water regulation can provide clinicians with a better appreciation for the complex physiology that underlies this intense sensation.
authors.affiliation: University of California San Francisco, School of Nursing, San Francisco, California 94143-0610, USA. shoshana.arai@nursing.ucsf.edu
authors.forename: Shoshana
authors.initials: S
authors.lastname: Arai
authors.forename: Nancy
authors.initials: N
authors.lastname: Stotts
authors.forename: Kathleen
authors.initials: K
authors.lastname: Puntillo
mesh_terms: D000322:Adrenergic Agonists / Q000378:metabolism; D016638:Critical Illness; D003681:Dehydration / Q000378:metabolism; D006801:Humans; D020896:Hypovolemia / Q000378:metabolism; D009994:Osmolar Concentration; D010465:Perception; D012084:Renin-Angiotensin System / Q000502:physiology; D013894:Thirst / Q000502:physiology*; D014667:Vasopressins / Q000378:metabolism
chemical_list: D000322:Adrenergic Agonists; D014667:Vasopressins